Confirmed on my side too, character started to do fence slow attack motion on random even when there are several zombies together.
This make me didn't want to use spears at all for now... this could simply made me grabbed.
Can you share your logs.zip file found in %UserProfile%\Zomboid?
Also can you share all “hs_err_pid” files found in your main game folder “Steam\steamapps\common\ProjectZomboid”?